Workpiece cutting method and band-saw machine

ABSTRACT

A workpiece cutting method utilizing a band-saw machine, includes the following steps of: guiding tooth tips of an endless band-saw blade provided on the band-saw machine in a direction of a workpiece by a band-saw blade guiding apparatus; and applying vibrations to the band-saw blade in a cutting direction to the workpiece so as to perform cutting of the workpiece by a vibration applying unit provided on the band-saw blade guiding apparatus.

TECHNICAL FIELD

The present invention relates to a workpiece cutting method utilizing aband-saw machine including an endless band-saw blade and a band-sawmachine used for the workpiece cutting method, and more particularly toa cutting method that applies vibrations in a cutting direction of aband-saw blade with respect to a workpiece for conducting application ofvibrations to perform cutting of the workpiece and a band-saw machineincluding a vibration applying unit that applies vibrations.

BACKGROUND ART

Types of band-saw machines include a horizontal band-saw machine and avertical band-saw machine. A band-saw blade used in band-saw machines isconfigured in an endless manner, by joining both end portions of aband-shaped saw blade by welding. A technique of swinging cutting hasbeen developed in order to reduce a cutting length to perform cutting ofa workpiece, at the time of cutting work of a workpiece is performedusing such an endless band-saw blade. This technique is disclosed in,for example, Japanese Patent Application Laid-open Publication No. JP-AS56-107825.

For example, in a horizontal band-saw machine, a workpiece is cut by theswinging cutting while alternately inclining a band-saw blade to a stateof diagonally right down and diagonally left down. That is, cutting workis performed on a workpiece by alternately repeating right downinclination and left down inclination of a saw blade housing includingthe band-saw blade slowly to incline the band-saw blade in the state ofdiagonally right down or diagonally left down. There has also beendeveloped a configuration where, when swinging cutting is performed, aband-saw blade is inclined in a state of diagonally right down anddiagonally left down by moving a guide roller included in a band-sawblade guiding apparatus that performs guiding of the band-saw blade in acutting direction. This technique is disclosed in, for example, JapanesePatent Application Laid-open Publication No. JP-A 2003-305613.

There is also a technique for adopting a configuration where awave-shaped undulation is formed on a back portion of a band-saw bladefor performing swinging cutting such as the one described above, andwhen a top portion of the undulation is positioned at one of band-sawblade guiding apparatuses, a bottom portion thereof is positioned at theother apparatus, to incline the band-saw blade to a state oforthogonally right down or orthogonally left down, thereby performingswinging cutting of a workpiece. This technique is disclosed in, forexample, Japanese Patent Application Laid-open Publication No. JP-AH9-300131.

Generally, gear cutting work is performed to form a band-saw blade usinga milling cutter in a gear cutting machine that is most suitable formass production. Accordingly, a band-saw width precision of the band-sawblade (a degree of variations of values obtained by measuring manydistances from a distal end of a tooth tip formed according to the gearcutting work to a back face of the band-saw blade) is determineddepending on a precision of the gear cutting machine, a precision of themilling cutter and the like. However, the band-saw width precision ofthe band-saw blade obtained by the work has variations in a range from0.03 to 0.05 mm, even if the blade is a favorable one.

Several hundred or more tooth tips are formed on one band-saw blade. Acutting amount per one tooth on the band-saw blade is examined below.When a height of a workpiece in a cutting direction is represented asHmm, a pitch of tooth tips of the band-saw blade is represented as Pmm,a rotational velocity (sawing rate) of the band-saw blade is representedas Vm/min, and a cutting time is represented as tmin, the cutting amountamm per one tooth is expressed by the following equation.a=(H×P)/(1000×V×t)mm

Next, in order to conduct specific calculations, representative samplesare extracted from a cutting condition table described in a blade(band-saw blade) catalogue for year 2000 issued by AMADA Co. Ltd.,Japan, who is the present applicant, and the calculations are performed.

(1) A pitch P of tooth tips of a band-saw blade conforming to S45C(JIS)φ100 is set to 7.3 mm.

Rotational velocity V of band-saw blade: 48 to 72 m/min

Cutting time t: 1.5 to 2.2 min

The minimum value of a cutting amount “a” per one tooth in thisconditions is(100×7.3)/(1000×72×2.2)=0.0046 mm,

and the maximum value thereof is(100×7.3)/(1000×48×1.5)=0.0101 mm.

(2) A pitch P of tooth tips of a band-saw blade conforming toSUS304(JIS) φ500 is set to 19.5 mm.

Rotational velocity V of band-saw blade: 17 to 26 m/min

Cutting time t: 90 to 168 min

The minimum value of a cutting amount “a” per one tooth in theconditions is(500×19.5)/(1000×26×168)=0.0022 mm,

and the maximum value thereof is(500×19.5)/(1000×17×90)=0.0064 mm.

As understood from the above, an average cutting amount per one tooth ofa band-saw blade is generally 0.01 mm or less.

However, as described above, the band-saw width precision of theband-saw blade includes variations in a range from 0.03 to 0.05 mm, evenif the blade is a favorable one. That is, the cutting amount per onetooth is ⅓ or less of the band-saw width precision, where there is aproblem that when cutting is performed in this state, only teeth with arelatively wide width of all the teeth including variations in band-sawwidth can work for cutting, and not all the teeth do not work.

It is easily conceived that teeth that move, but only gall a cuttingface without removing chips, are present. Presumably, it is conceivablethat the teeth that move in a galling manner generate uncomfortablenoises and extra heat.

The present invention has been achieved in order to solve the problem,and an object of the invention is to provide a cutting method that canperform effective cutting by controlling a band-saw blade such that allteeth corresponding to a workpiece can cut in the workpiece, and aband-saw machine used in the cutting method.

DISCLOSURE OF THE INVENTION

To achieve the above object, a first aspect of the present inventionprovides a workpiece cutting method utilizing a band-saw machine,comprising steps of: guiding tooth tips of an endless band-saw bladeprovided on the band-saw machine in a direction of a workpiece by aband-saw blade guiding apparatus; and applying vibrations of theband-saw blade on the workpiece in a cutting direction to performcutting of the workpiece by a vibration applying unit provided on theband-saw blade guiding apparatus.

A second aspect of the present invention provides the workpiece cuttingmethod according to the first aspect, wherein the vibrations in thecutting direction are applied to the band-saw blade in a state thatrespective vibration applying units provided on a pair of the band-sawblade guiding apparatuses are synchronized with each other or therespective vibration applying units are asynchronous with each other.

A third aspect of the present invention provides the workpiece cuttingmethod according to the first aspect or the second aspect, wherein anamplitude of the vibrations of the band-saw blade in the cuttingdirection is in a range from about 0.03 to 0.5 mm, and a frequency ofthe vibrations is in a range from several Hz to several hundreds Hz.

To achieve the above object, a fourth aspect of the present inventionprovides a band-saw machine comprising: an endless band-saw blade havinga plurality of teeth; a band-saw blade guiding apparatus that guidestooth tips on the band-saw blade toward a workpiece to be cut; and avibration applying unit that is provided on the band-saw blade guidingapparatus, for applying vibrations of the band-saw blade on theworkpiece in a cutting direction to the band-saw blade.

A fifth aspect of the present invention provides the band-saw machineaccording to the fourth aspect, wherein the vibration applying unitincludes a non-circular rotating member that can press a back portion ofthe band-saw blade directly or indirectly.

A sixth aspect of the present invention provides the band-saw machineaccording to the fourth aspect, wherein the vibration applying unitincludes a hammer that can hit a back portion of the band-saw bladedirectly or indirectly.

A seventh aspect of the present invention provides the band-saw machineaccording to the fourth aspect, wherein the vibration applying unit isconfigured so as to vibrate a backup holding member including a backportion pressing member that can press a back portion of the band-sawblade.

To achieve the above object, an eighth aspect of the present inventionprovides a band-saw machine comprising: an endless band-saw blade havinga plurality of teeth; a plurality of band-saw blade guiding apparatusesthat guide tooth tips on the band-saw blade toward a workpiece to becut, where one of the band-saw blade guiding apparatuses is provided soas to be movable in a direction of approaching to and separating fromthe other one; and

vibration applying units that are provided on the plurality of band-sawblade guiding apparatuses, for applying vibrations of the band-saw bladeon the workpiece in a cutting direction, wherein the respectivevibration applying units are coupled to each other via a powertransmission unit.

Accordingly, according to the present invention, since cutting of aworkpiece is performed by applying vibrations in a cutting direction ofthe band-saw blade with respect to the workpiece to the band-saw blade,a form where all teeth of the band-saw blade corresponding to theworkpiece can cut in the workpiece is made, so that efficient cuttingcan be performed.

Since chips are finely divided, discharge property of the chips isimproved, and since heat generation due to cutting resistance and heatradiation are alternately repeated, temperature of the band-saw bladeand the workpiece is prevented from being higher. Accordingly,elongation of life of the band-saw blade can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory front view showing an entire configuration of ahorizontal band-saw machine as one example of a band-saw machine;

FIG. 2(A) and FIG. 2(B) are explanatory diagrams of a configuration forapplying vibrations in a cutting direction to a band-saw blade providedin the band-saw machine and of an operation of the saw blade;

FIG. 3(A) and FIG. 3(B) are explanatory diagrams of a configuration forapplying vibrations in a cutting direction to a band-saw blade providedin the band-saw machine and of an operation of the saw blade;

FIG. 4(A) to FIG. 4(C) are explanatory diagrams showing variousconfigurations for applying vibrations in a cutting direction to theband-saw blade;

FIG. 5(A) and FIG. 5(B) are explanatory diagrams showing configurationsfor applying vibrations in a cutting direction to the band-saw blade;

FIG. 6(A) and FIG. 6(B) are explanatory diagrams showing configurationsfor applying vibrations in a cutting direction to the band-saw blade;

FIG. 7(A) to FIG. 7(D) are explanatory diagrams showing configurationsfor applying vibrations in a cutting direction to the band-saw blade;

FIG. 8 is an explanatory diagram showing a configuration for applyingvibrations in a cutting direction to the band-saw blade;

FIG. 9 is an explanatory diagram showing a configuration for applyingvibrations in a cutting direction to the band-saw blade;

FIG. 10 is an explanatory diagram showing a configuration for applyingvibrations in a cutting direction to a band-saw blade according toanother embodiment;

FIG. 11 is a side explanatory diagram of main parts for applyingvibrations in a cutting direction to a band-saw blade; and

FIG. 12 is an explanatory diagram showing a configuration for applyingvibrations in a cutting direction to a band-saw blade according toanother embodiment.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will be explained belowbased on FIG. 1 to FIG. 12.

First, with reference to FIG. 1, a band-saw blade 1 includes a baseframe 3, and the base frame 3 includes a vice device 5 that can fix aworkpiece W to be cut. A saw-blade frame 9 including an endless band-sawblade 7 is provided on the base frame 3 so as to be movable in relativedirections of approaching to and separating from the workpiece W, and anactuator 11 for a cutting operation such as a hydraulic cylinder formoving the saw-blade frame 9 is also provided thereon. Further, guidearms 13A, 15A including band-saw guiding apparatuses 13, 15 for guidingtooth tips on the band-saw blade 7 toward the workpiece W at theirdistal ends (lower ends) are provided on the saw blade housing 9. As iswell known, the guide arms 13A, 15A are supported by a guide beam 14provided on the saw blade housing 9, where one guide arm 13A is fixed onthe guide beam 14. The other guide arm 15A is provided such that itsposition can be adjusted in directions of approaching to and separatingfrom the guide arm 13A corresponding to the size of the workpiece W.Since the configuration of this type of band-saw machine is well known,detailed explanations thereof will be omitted.

In thus configured band-saw machine 1, the band-saw blade 7 is drivenand run, in a state that the band-saw blade 7 is separated from theworkpiece W according to an operation of the actuator 11, and the sawblade housing 9 is moved in a cutting direction of the band-saw blade 7to the workpiece W according to an operation of the actuator 11, so thatcutting of the workpiece W is performed by the band-saw blade 7.

When cutting of the workpiece W is performed by driving and running theband-saw blade 7 as described above, and moving the band-saw blade 7 ina cutting direction with respect to the workpiece W, the band-saw blade7 is guided and supported by the band-saw blade guiding apparatuses 13,15 at both sides of the workpiece W. Accordingly, the band-saw blade 7is put in a state that it is resiliently deformed and slightly bent dueto a reaction force against cutting resistance from the workpiece Wbetween the band-saw blade guiding apparatuses 13, 15. When there areslight differences in height among respective saw-teeth on the band-sawblade 7 due to a manufacturing error or the like, there may be someteeth that do not contribute to cutting of the workpiece W.

In the present embodiment, it is configured that vibration applyingunits are provided on the band-saw blade guiding apparatuses 13, 15, andvibrations to the workpiece W in cutting direction are applied to theband-saw blade 7 by the vibration applying units. In more detail, theband-saw guiding apparatuses 13, 15 clamp a barrel portion of theband-saw blade 7 from its both sides and abut on a back portion of theband-saw blade 7 to support the band-saw blade 7, thereby guiding toothtips of the band-saw blade 7 toward the workpiece W. The band-sawguiding apparatuses 13, 15 include rotating members 19A, 19B rotated(revolved) by rotating actuators 1 7A, 1 7B such as motors, as shownconceptually and schematically in FIG. 2(A) and FIG. 2(B).

The rotating members 19A, 19B rotate while abutting on the back portionof the band-saw blade 7, and are formed in a non-circular shape whererecessed portions (portions with a small radius from a rotationalcenter, namely, portions with a small distance from the rotationalcenter to a contact point on the band-saw blade 7) 21A, 21B andprojecting portions (portions with a large radius from the rotationalcenter, namely, portions with a large distance from the rotationalcenter to the contact point on the band-saw blade 7) 23A, 23B areprovided at approximately equal pitches.

Accordingly, as shown in FIG. 2(A), the recessed portions 21A, 21 B inthe respective rotating members 19A, 19B are opposed to the back portionof the band-saw blade 7, and while the band-saw blade 7 runs (moves),for example horizontally, to perform cutting of the workpiece W in thisstate, the projecting portions 23A, 23B of the rotating members 19A, 19Bare opposed to the back portion of the band-saw blade 7 by rotating therotating actuators 17A, 17B synchronously, so that the band-saw blade 7is pressed in a cutting direction of the band-saw blade 7 by theprojections 23A, 23B of the rotating members 19A, 19B. Therefore, theband-saw blade 7 actively conducts cutting of the workpiece W (see FIG.2(B)).

When both of the projections 23A, 23B of the rotating members 19A, 19Babut on the back portion of the band-saw blade 7, the band-saw blade 7is again moved horizontally, so that cutting of the workpiece W isprogressed by respective teeth on the band-saw blade 7, as shown in FIG.3(A). At this time, heat is generated due to cutting resistance.

Next, when the rotating members 19A and 19B are further rotated to comeinto a state shown in FIG. 3(B), the recessed portions 21A, 21B of therotating members 19A, 19B are again opposed to the back portion of theband-saw blade 7. At this time, it is in a state that pressure from theband-saw blade 7 is temporarily released, and the band-saw blade 7 movesso as to be slightly separated from the workpiece W (see FIG. 3(B)).When it comes to a state shown in FIG. 3(B), in other words, when theband-saw blade 7 moves so as to be slightly separated from the workpieceW, it acts to remove cut chips from the workpiece W so that the chipsare removed from the workpiece W.

In the state shown in FIG. 3(B) to the state shown in FIG. 2(A),generation of heat is suppressed due to relative reduction of thecutting resistance and the heat is radiated, so that the temperature ofthe band-saw blade 7 and the workpiece W can be prevented from beinghigher.

As described above, according to the band-saw machine of the presentinvention, since the recess portions 21A, 21B and the projectingportions 23A, 23B of the rotating members 19 a, 19B are alternatelyopposed to the back portion of the band-saw blade 7 to abut thereto, theband-saw blade 7 is vibrated in the cutting direction with respect tothe workpiece W. Therefore, when a cutting operation is performed by theband-saw blade 7 while the saw blade frame 9 is being moved in thecutting direction to the workpiece W with respect thereto, the cuttingoperation of the band-saw blade 7 on the workpiece W is performed withimpact, and fast and slight movement of the band-saw blade 7 in aseparating direction from the workpiece W is repeated by vibrating theband-saw blade 7 in the cutting direction.

Therefore, when the band-saw blade 7 is pressed and moved in thedirection of the workpiece W by the rotating members 19A, 19B, all thesaw-teeth 7T opposed to the workpiece W are put in a cutting form, andcutting of the workpiece W is performed effectively, so that efficientcutting work can be performed. When the band-saw blade 7 is moved to beseparated from the workpiece W slightly, it acts to remove cut chipsfrom the workpiece W so that the chips are removed from the workpiece W,which results in reduction of the cutting resistance. Accordingly,discharge property of chips is improved due to fine divisions of thechips, and heat generation due to the cutting resistance can be easilysuppressed. Accordingly, elongation of life of the band-saw blade 7 canbe achieved.

Note that, in the above explanation, the case where the recessedportions 21A, 21B or the projecting portions 23A, 23B of the rotatingmembers 19A, 19B are simultaneously opposed and pressed to the backportion of the band-saw blade 7 has been explained. However, it is alsopossible to adopt a configuration where the recess portion of onerotating member of the rotating members 19A, 19B and the projectingportion of the other rotating member are simultaneously opposed to theback portion of the band-saw blade 7. That is, it is possible to rotatethe left and right rotating members 19A, 19B at phases different fromeach other, or rotate the left and right rotating members 19A, 19B atrotational numbers different from each other. Even in these cases,vibrations in the cutting direction can be applied to the band-saw blade7, so that the above described effects can be achieved.

It is desirable that an amplitude of vibrations of the band-saw blade 7to the workpiece W in the cutting direction is in a range of about 0.03to 0.5 mm in view of a band-saw width precision due to a manufacturingerror of the band-saw blade 7. That is, when a cutting operation of theworkpiece W by the band-saw blade 7 is performed, cutting of thesaw-teeth 7T on the band-saw blade 7 to the workpiece W is conductedeffectively by vibrating the band-saw blade 7 in the cutting direction.However, when a cutting amount is excessively large, load acting on thesaw-teeth 7T becomes large, and chipping of a tooth can occur in somecases. In order to make almost all the saw-teeth 7T contribute tocutting of the workpiece W, it is desirable that vibrations aregenerated with such an extent of amplitude in which an error in theband-saw width precision can be absorbed.

While a frequency of the vibrations in the cutting direction applied tothe band-saw blade 7 depends on the magnitude of a running velocity ofthe band-saw blade 7, it is preferably set to a range from several Hz toseveral hundreds Hz. That is, the number of repetitions of cutting ofthe respective saw-teeth 7T to the workpiece W is increased and acutting length of the workpiece W per one tooth of the band-saw blade 7is decreased according to increase of the frequency. Accordingly,generated chips become shorter, and discharge property is improved.However, the number of repetitions of cutting of the saw-teeth 7T to theworkpiece W with impact and application of large load to the workpiece Wdue to cutting resistance is increased. Therefore, with life reductiondue to repetitive load acting on the respective saw-teeth 7T on theband-saw blade 7 in consideration, it is desirable that the frequency isset in a range of several Hz to several hundreds Hz. When the band-sawblade 7 has a configuration where carbide chips or the like are brazedto tooth tips, increase in frequency is not desirable, because missingof the carbide chip due to application of load with impact thereto ispromoted.

When a relationship between the running velocity of the band-saw blade 7and the number of vibrations thereof in the cutting direction have acertain relationship, as shown in FIGS. 2(A), 2(B) and FIGS. 3(A), 3(B),each time when the saw-teeth 7T move by a distance corresponding toabout one pitch of the saw-teeth 7T on the band-saw blade 7, cutting dueto vibrations of the band-saw blade 7 to the workpiece W is repeated, sothat lengths of chips become approximately equal to the pitch of thesaw-teeth 7T. That is, the lengths of the chips thus generated becomeconsiderably short as compared with the lengths of chips generated at anordinary cutting time where vibrations are not applied in the cuttingdirection of the band-saw blade 7 with respect to the workpiece W or ata vibration-cutting time. Accordingly, the discharge property of chipsis improved.

Cutting of the saw-teeth 7T to the workpiece W is performed by applyingvibrations in the cutting direction of the band-saw blade 7, as shown inFIG. 2(B), FIG. 3(A), biting property of respective tooth 7T to theworkpiece W is improved, where even a workpiece having a tendency ofexhibiting work hardening is cut from its portion below a work hardeninglayer thereof, so that cutting work can be easily performed.

As a configuration for applying vibrations to the band-saw blade 7 inthe cutting direction, as shown in FIG. 4(A), the rotating members 19A,19B can be formed in a polygonal shape, or as shown in FIGS. 4(B), 4(C),the rotating members 19A, 19B can be formed as an eccentric cam or aneccentric roller with an appropriate shape. That is, when the rotatingmembers 19A, 19B rotated by the actuators are formed in a non-circularshape, various shapes can be adopted therefor. Also, a pair of rotatingmembers 19A, 19B can be formed in a different shape from each other.

As shown in FIG. 5, it is also possible to adopt a configuration wherebackup rollers 29 that abut on the back portion of the band-saw blade 7to restrict movement toward the back portion are rotatably provided on aswinging lever 27 provided so as to be swingable about a pivoting shaft25 in the band-saw blade guiding apparatus 13, 15, and a non-circularrotating member 19 is caused to abut on the backup roller 29. Accordingto this configuration, vibrations in the cutting direction can beindirectly applied to the band-saw blade 7 via the backup roller 29, dueto the rotations of the rotating member 19 caused by the actuator 17.

As shown in FIG. 6(A), it is also possible to adopt a configurationwhere one end of the swinging lever 27 is extended and a rotating member19 rotated by the actuator is provided at the swinging lever 27. In thiscase, as shown in FIG. 6(B), a configuration where a backup chip 31 isprovided on the swinging lever 27 instead of the backup roller 29 can bealso adopted.

As shown in FIG. 7(A), it is also possible to adopt a configurationwhere the backup roller 29 is provided on one end of the swinging lever27 and a rotating member 19 rotated by the actuator is provided on theother end thereof. As shown in FIG. 7(B), a configuration where rotatingmembers 19 are provided at both ends of the swinging lever 27 can bealso adopted. In this case, as shown in FIG. 7(C), a configuration whereboth rotating members 19 are set to have different diameters can be alsoadopted. Further, as shown in FIG. 7(D), a configuration where a belt 33with projecting portions disposed on an outer peripheral face thereof atappropriate intervals are wound around backup rollers 29 can be alsoadopted.

That is, various configurations can be adopted as the configuration forapplying vibrations in the cutting direction to the band-saw blade 7 bya rotating member rotated by an actuator.

Further, as the configuration where vibrations in the cutting directionare applied to the band-saw blade 7, a configuration such as the oneshown in FIG. 8 can be also adopted. That is, it is configured that aflange portion 35F that abuts on the back portion of the band-saw blade7 to support the band-saw blade 7 is provided on one of a pair of guiderollers 35A, 35B clamping the band-saw blade 7 from both sides thereofto guide the same and projecting portions 35P are provided on a portionof the flange portion 35F that abuts on the back portion of the band-sawblade 7 to support the band-saw blade 7 at appropriate intervals isadopted in the band-saw blade guiding apparatus. According to thisconfiguration, it is in a state that the band-saw blade 7 is presseddownwardly each time when the back portion of the band-saw blade 7 issupported by the projecting portion 35P, so that vibrations in thecutting direction can be applied to the band-saw blade 7.

Further, as the configuration where vibrations in the cutting directionare applied to the band-saw blade 7, as shown in FIG. 9, it is alsopossible to adopt a configuration where an actuator 37, for example asolenoid or a mini-cylinder, is provided in the band-saw blade guidingapparatus 13, 15, and the back portion of the band-saw blade 7 isdirectly or indirectly hit by an operation lever 39 provided on theactuator 37 so as to reciprocate, or hit by a hammer 41 provided at adistal end of the operation lever 39.

According to the above configuration, an operation cycle of the actuator37 can be changed arbitrarily, and a biting force of the saw-teeth onthe band-saw blade 7 to the workpiece can be controlled by controllingoutput of the actuator 3 7. Further, by controlling a stroke amount ofthe operation lever 39, amplitude of the vibrations in the cuttingdirection applied to the band-saw blade 7 can be controlled. Therefore,according to the configuration, the number of vibrations of the band-sawblade 7 in the cutting direction, the amplitude of the vibrations, and acutting force (a vibrating force) of the band-saw blade 7 can becontrolled corresponding to the material, the shape, the size and thelike of a workpiece.

To summarize, in the present embodiment, as understood from the aboveexplanations, the vibration applying units are provided on the band-sawblade guiding apparatuses 13, 15 that hold and guide the band-saw blade7 so as to direct the tooth tips on the band-saw blade 7, or providedclose to the band-saw blade guiding apparatuses 13, 15, and cutting ofthe workpiece W is conducted by applying vibrations of the band-sawblade 7 in the cutting direction to the workpiece W utilizing thevibration applying units. Therefore, even if there are some differencesin height among the saw-teeth 7T on the band-saw blade 7, all of thesaw-teeth 7T on the band-saw blade 7 contribute to cutting of theworkpiece W, so that efficient cutting can be conducted.

As described above, since cutting property of the saw-teeth on aworkpiece is improved by vibrating the band-saw blade 7 in the cuttingdirection, even a workpiece having a tendency of exhibiting workhardening can be cut favorably and lengths of chips generated duringcutting of the workpiece can be shortened, so that discharge property ofchips can be improved.

The present invention is not limited to the embodiments described above,and can be embodied in other various forms by appropriate modifications.That is, in the above explanations, the effect that the rotating members19 a, 19B are rotationally driven by the rotating actuators 17A, 17Bsuch as motors has been explained. However, it can be configured thatthe rotating members 19A, 19B are rotated according to rotations of theband-saw blade 7, without using the rotating actuators.

FIG. 10 shows another embodiment. In this embodiment, a rotational shaft55 is rotatably supported to a gearbox 53 attached on an upper portionof one guide arm 13A via a bracket 51. The rotational shaft 55 isrotated by a motor 57 attached on the gearbox 53. Transmission ofrotations from the motor 57 to the rotational shaft 55 is performed viaa bevel gear mechanism, a worm gear mechanism or the like provided inthe gearbox 53.

A cam 59 with an appropriate shape, for example a polygonal shape, isattached to one end of the rotational shaft 55, and a spline shaft 55Sextending horizontally toward the other guide arm 15A in parallel withthe guide beam 14 is provided on the other end thereof. The spline shaft55S is spline-fitted in a spline sleeve 63 to be slidable in an axialdirection relative to the spline sleeve 63, which is supported to abearing 61 provided on an upper portion of the guide arm 15A such thatonly rotations thereof are allowed. A cam 65 similar to the cam 59 isattached to the other end of the spline sleeve 63.

Brackets 67 (see FIG. 11) are provided on upper portions of the guidearms 13A, 15A corresponding to the cams 59, 65, and swinging arms 71 aresupported to the brackets 67 via pivoting shafts 69 so as to bevertically swingable. Cam followers 73 pressed downwardly by therespective arms 59, 65 are rotatably provided on the respective swingingarms 71. Upper end portions of pressing rods 75 supported by therespective guide arms 13A, 15A to be movable vertically abut on lowerfaces of distal ends of the respective swinging arms 71.

Lower ends of the respective pressing rods 75 abut on backup holdingmembers 77 provided on the band-saw blade guiding apparatuses 13, 15.That is, clamping members 79 for clamping and guiding the band-saw blade7 from both sides thereof are provided on the band-saw blade guidingapparatuses 13, 15, like ordinary band-saw blade guiding apparatuses. Aproximal end portion of the backup holding member 77 including a backportion pressing member 81 such as a backup or a backup roller that canpress the back portion of the band-saw blade 7 is pivoted via a pivotingshaft 83 to be vertically rotatable, and a distal end portion (a lowerend portion) of the pressing rod 75 abuts on a distal end of the backupholding member 77 so as to press the back portion pressing member 81toward the band-saw blade 7.

With the above configuration, the cams 59, 65 on the sides of the guidearms 13A, 15A are simultaneously rotated by the rotational shaft 55 thatis one example of a power transmission unit. Accordingly, when therespective swinging arms 71 are swung downwardly via the respective camfollowers 73 according to rotations of the cams 59, 65, the backupholding members 77 are pressed toward the band-saw blade 7 by the distalend portions of the respective pressing rods 75. Accordingly, whenpressings from the cams 59, 65 are released (when recesses of the cams59, 65 correspond to the cam followers 73), it comes to a state that theband-saw blade 7 and the pressing rods 75 are returned back due tocutting resistance in a principal component force (a back componentforce).

That is, in the configuration, cutting of a workpiece can be performedby applying vibrations in the cutting direction to the band-saw blade 7.

As the configuration for applying vibrations of the band-saw blade 7 ona workpiece in the cutting direction to the band-saw blade 7, it is alsopossible to adopt a configuration where a cam follower CF provided onthe backup holding member 77 is moved vertically by an appropriate cam Csuch as a cylindrical cam or a face cam rotated by a motor M provided onthe guide arm 13A (15A), as shown in FIG. 12. Further, a configurationwhere a supporting block 85 including a backup roller 29 or the like ismoved vertically by an actuator AC such as a hydraulic cylinder or asolenoid can be also adopted.

As the configuration of applying vibrations of the band-saw blade 7 on aworkpiece in the cutting direction to the band-saw blade 7, it is alsopossible to adopt a configuration where the guide beam 14 supporting theguide arms 13A, 15A is vibrated vertically (the cutting direction of theband-saw blade 7) by an appropriate actuator, or a configuration wherethe saw blade housing 9 is vibrated by driving the actuator 11 for acutting operation in a vibrating manner so that vibrations are appliedto the band-saw blade 7 in the cutting direction. It is also possible toadopt a configuration where a motor including an eccentric weight isattached to the saw blade housing 9, the saw blade housing 9 is vibratedby rotating the motor, and vibrations of the band-saw blade 7 on aworkpiece in the cutting direction are applied to the band-saw blade 7by the vibrations.

That is, as the configuration for applying vibrations of the band-sawblade 7 on a workpiece in the cutting direction to the band-saw blade 7,it is possible to adopt various configurations, such as a configurationfor directly applying vibrations to the band-saw blade 7, or aconfiguration for applying vibrations to a configuration supporting theband-saw blade 7 to indirectly apply vibrations to the band-saw blade 7.

The present invention is not limited to the above and aforementionedembodiments of the invention, and can be embodied in other various formsby appropriate modifications.

The disclosures of Japanese Patent Application No. 2004-217302 (filed onJul. 26, 2004) and Japanese Patent Application No. 2005-105112 (filed onMar. 31, 2005) are incorporated by reference herein in their entirety.

1. A workpiece cutting method utilizing a band-saw machine having anendless band-saw blade with a plurality of teeth having tooth tips, apair of band-saw blade guides and a pair of vibration applyingapparatuses, comprising: guiding the tooth tips of the endless band-sawblade with the pair of band-saw blade guides towards a workpiece so asto cut the workpiece; and applying vibrations to the band-saw blade, viathe pair of vibration applying apparatuses, in a cutting direction wherethe band-saw blade approaches the workpiece in a manner such that thepair of vibration applying apparatuses simultaneously apply vibrationsto the band-saw blade, and the tooth tips of the band-saw blade therebysimultaneously approach the workpiece in the cutting direction, whereinthe band-saw blade approaches the workpiece at a speed not smoothlyaccelerated so as to cut the workpiece, and temporarily moves away fromthe workpiece at a speed not smoothly accelerated so as to remove cutchips from the workpiece, and a frequency of the vibrations iscorrelated to a running velocity of the band-saw blade, so that thelengths of chips generated by cutting the workpiece are approximatelyequal to a pitch of the teeth.
 2. The workpiece cutting method accordingto claim 1, wherein the pair of vibration applying apparatuses areprovided on the pair of band-saw blade guides.
 3. A workpiece cuttingmethod utilizing a band-saw machine having an endless band-saw bladewith a plurality of teeth having tooth tips, a pair of band-saw bladeguides and a pair of vibration applying apparatuses, comprising: guidingthe tooth tips of the endless band-saw blade with the pair of band-sawblade guides towards a workpiece so as to cut the workpiece; andapplying vibrations to the band-saw blade, via the pair of vibrationapplying apparatuses, in a cutting direction where the band-saw bladeapproaches the workpiece in a manner such that the pair of vibrationapplying apparatuses simultaneously apply vibrations to the band-sawblade, and the tooth tips of the band-saw blade thereby simultaneouslyapproach the workpiece in the cutting direction, wherein an amplitude ofthe vibrations of the band-saw blade in the cutting direction is in arange from about 0.03 to 0.5 mm, and a frequency of the vibrations is ina range from several Hz to several hundred Hz, wherein the band-sawblade approaches the workpiece at a speed not smoothly accelerated so asto cut the workpiece, and temporarily moves away from the workpiece at aspeed not smoothly accelerated so as to remove cut chips from theworkpiece, and a frequency of the vibrations is correlated to a runningvelocity of the band-saw blade, so that the lengths of chips generatedby cutting the workpiece are approximately equal to a pitch of theteeth.
 4. A workpiece cutting method utilizing a band-saw machine havingan endless band-saw blade with a plurality of teeth having tooth tips, aband-saw blade guide and a vibration applying apparatus, comprising:guiding the tooth tips of the endless band-saw blade with the band-sawblade guide towards a workpiece so as to cut the workpiece; and applyingvibrations to the band-saw blade, via the vibration applying apparatus,in a cutting direction where the band-saw blade approaches theworkpiece, wherein the vibrations in the cutting direction are appliedto the band-saw blade by vibration applying units provided on a pair ofband-saw blade guiding apparatuses, an amplitude of the vibrations ofthe band-saw blade in the cutting direction is in a range from about0.03 to 0.5 mm, and a frequency of the vibrations is in a range fromseveral Hz to several hundred Hz, wherein the band-saw blade approachesthe workpiece at a speed not smoothly accelerated so as to cut theworkpiece, and temporarily moves away from the workpiece at a speed notsmoothly accelerated so as to remove cut chips from the workpiece, and afrequency of the vibrations is correlated to a running velocity of theband-saw blade, so that the lengths of chips generated by cutting theworkpiece are approximately equal to a pitch of the teeth.